1. Field of the Invention
Halogenated cyclic monomers, i.e., dioxoles and dioxolanes, preparation thereof and polymers thereof.
2. State of the Art
U.S. Pat. No. 2,925,424 discloses cyclic fluoroketals of the formula ##STR1## prepared by reacting fluoroketones with .beta.-haloethanol. R.sub.x and R.sub.y are perhalohydrocarbyl radicals of 1 to 7 carbon atoms, and R.sub.z is a divalent hydrocarbyl or halohydrocarbyl radical of 1 to 12 carbon atoms.
U.S. Pat. Nos. 3,865,845 and 3,978,030 disclose fluorinated dioxoles of the formula ##STR2## where R.sup.1 and R.sup.2 are both perhalogenated hydrocarbyl radicals of 1 to 3 carbon atoms containing at least one F atom, and preparation of said dioxoles by reacting the corresponding dioxolanes with Mg. The dioxolanes are prepared by fluorination with SbF.sub.3 -SbCl.sub.5 at 120.degree. C. of 2,2-bis-(perhaloalkyl)-4,4,5,5-tetrachloro-1,3-dioxolanes, which in turn are prepared from haloketones in accordance with the method described in U.S. Pat. No. 2,925,424 cited above.
U.S. Pat. No. 3,555,100 discloses the decarbonylation of fluorocarboxylic acid fluorides in the presence of SbF.sub.5.
U.S. Pat. No. 3,308,107 discloses perfluoro-2-methylene-4-methyl-1,3-dioxolane, its preparation from perfluoro-2,4-dimethyl-2-fluoroformyl-1,3-dioxolane, and polymers thereof.
U.S. Pat. No. 3,532,725 discloses the photochlorination of alkyl and aralkyl ester groups of fluorinated esters in the presence of Cl.sub.2, UV radiation and, optionally, CCl.sub.4 as solvent.
U.S. Pat. No. 3,557,165 discloses the conversion to acyl halides, in the presence of Lewis acids, of fluorinated esters wherein the ester groups contain polyhalogenated alkyl or aralkyl groups. The disclosed Lewis acids include FeCl.sub.3, SbCl.sub.5, ZnCl.sub.2, ZnCl.sub.4, BF.sub.3, BCl.sub.3, MoCl.sub.5, tin chlorides and metal chlorides, bromides and iodides such as ZrI.sub.4 and antimony bromide.
U.S. Pat. No. 3,316,216 discloses the preparation of fluorinated dioxolanes of the formula ##STR3## where R, R' and R" can include H, hydrocarbyl, haloalkyl and various other carbon-containing groups, and X and X.sup.1 can include H, halogen and perfluoroalkyl, from fluoroketones and epoxides.
U.S. Pat. No. 3,324,144 discloses fluorodioxolanes ##STR4## prepared from ketones and epoxides.
U.S. Pat. No. 3,749,791 discloses halogen-substituted 2,2-bis(trifluoromethyl)-1,3-dioxolanes ##STR5## where X is Cl or F and X' is H, Cl, or F, and their preparation by hydrogenation of 2,2-bis(trifluoromethyl)-1,3-dioxolane.